1. Field of the Invention
The present invention relates to a method of assigning signal channels which assigns a signal channel to be added to every node, which is arranged at a predetermined position on an optical transmission line and adds signals of a predetermined channel to the optical transmission line, and an optical communication system including nodes each adding signals of a channel assigned by this assigning method to the optical transmission line.
2. Related Background Art
In a wavelength division multiplexing (WDM: wavelength Division Multiplexing) optical communication system for transmitting signals having wavelengths different from each other, at a node provided on an optical transmission line, there is a case where signals of a predetermined wavelength (predetermined channel) is dropped (received by the node and is not transmitted to a downstream optical transmission line), or signals of a predetermined channel is added (transmitted from the node and is not transmitted to a downstream optical transmission line). An optical communication system for adding signals of a predetermined channel to an optical transmission line from a node is disclosed in, for example, Japanese Patent Laid-Open No.13356/1998, No.172449/1997, and the like.